At around 16 weeks you will probably be offered an ultrasound scan so that you can see your baby for the first time. A scan can be carried out at any stage of pregnancy, but is usually offered between 16 and 20 weeks (although a dating scan may be offered as early as ten weeks).

The procedure is completely painless. High-density sound waves are used to create a picture of your baby in the uterus, and you will be able to see this on a screen. The best picture are obtained when you have a full bladder so you will be asked to drink a lot of fluid beforehand. You lie on a couch and your stomach is lubricated so that the person performing the scan can pull the scanner smoothly across it. The picture that appears on the screen may not be clear, so ask the radiographer to explain the images to you, if you are unsure of what you are seeing.

The fetus’s age can be determined from a scan; it also shows up most abnormalities of the head and spine that may have occurred and will detect the presence of twins. The exact position of the placenta and the fetus can be seen, so if there are any problems, for example when the placenta is situated very low down, extra care will be taken throughout your pregnancy.

Twins

There is about a one in 80 chance that you and your partner will conceive twins. However, you are more likely to give birth to twins if you have a history of them in your, or your partner’s, family.

Identical twins come from one egg which, once fertilized, then splits into two separate cells. Each of the cells then grown into a separate fetus, but they usually share the same placenta. Because identical twins originally came from the same cells they are always the same sex and look like each other.

Non-identical twins, are the result of two eggs being fertilized by two different sperm at the same time. Each fetus has its own placenta and the sexes of the babies may differ.

Fraternal twins usually don’t look any more alike than brothers and sisters who are born years apart.